Permanent caravan accommodation in and surrounding the London area?

Question:Im considering caravan accommodation to cut down my expenses.
Would ideally like to live in someones yard or driveway. Not too keen on the caravan parks, a bit nervous.

Please send me any info relating to this.

thanx

Answers:
Not convinced it would be much cheaper than a room in a house. You would also need to pay for shared facilities in the main house, i.e. kitchen and shower. This sort of accommodation is not openly advertised as it's in a grey area of planning law.